放映镜头脏了，不能随便找个抹布进行擦拭，需要专业的、柔软的、不易脱毛毛的擦镜布。（）
参考答案：对
---yes, _______.We’d better buy some.
A. run out of; we have run it out
B. run out of; our food has run out
C. run out of; out food has been run out
D. run out; our food has run out
互换是指交易双方同意在约定的时间长度内，按照指定货币以约定的形式交换一系列现金流支付的行为。
